The purpose of this project is to prepare a wide variety of alkyl and glycosyl derivatives of colchicine and alkylthiocolchicines and their analogs, which have shown muscle relaxant and antimitotic activity. These compounds will also be tested for possible activity against intracrania leukemia. The preparations of a fairly large number of colchicine and alkylthiocolchicine derivatives have been accomplished and the preparations of a wide variety of colchincine and alkylthiocolchicine derivatives are in progress. The compounds prepared have been tested for their antileukemic activities in in vitro tissue culture. These preliminary data have shown some interesting results. They are being submitted to the Drug Development Branch, Drug Research and Development, Chemotherapy, NCI, for evaluation of their intracrania antileukemic activity.